Method of manufacturing image display apparatus

ABSTRACT

In the method of manufacturing an image display apparatus according to the present invention, a liquid photocurable resin composition that does not contain a thermal polymerization initiator is coated on the surface of a light-transmissive cover member including a light shielding layer or the surface of an image display member in a thickness thicker than that of the light shielding layer, and thereafter UV rays are irradiated in that state for curing to form a light-transmissive cured resin layer. Then, the image display member and the light-transmissive cover member are laminated to each other via the light-transmissive cured resin layer to obtain an image display apparatus.

TECHNICAL FIELD

The present invention relates to a method of manufacturing an imagedisplay apparatus by bonding and laminating an image display member suchas a liquid crystal display panel and a light-transmissive cover membersuch as a transparent protective sheet disposed on the surface side ofthe image display member, via a light-transmissive cured resin layer.

BACKGROUND ART

An image display apparatus such as a liquid crystal display panel usedin information terminals such as a smartphone is manufactured bydisposing a photocurable resin composition between an image displaymember such as a liquid crystal display panel or an organic EL displaypanel, and a light-transmissive cover member; and thereafter irradiatingUV rays to the resin composition so as to cure into a light-transmissivecured resin layer, thereby bonding and laminating the image displaymember and the light-transmissive cover member (Patent Literature 1).

In the image display apparatus, a light shielding layer for improvingthe brightness and contrast of a display image is disposed around anouter edge on the image display member-side surface of thelight-transmissive cover member. For this reason, curing of thephotocurable resin composition disposed between such a light shieldinglayer and the image display member does not sufficiently proceed, andtherefore, sufficient adhesion cannot be obtained. Accordingly, it isconcerned that a peeling between the transmissive cover member and theimage display member is caused, and that moisture invades a spacebetween the transmissive cover member and the image display member,resulting in a reduced image quality.

Under such circumstances, there is proposed a method of: mixing athermal polymerization initiator in a photocurable resin composition toobtain a heat- and photocurable resin composition; coating the surfaceof the light-transmissive cover member having the light shielding layerformed thereon with the heat- and photocurable resin composition;laminating the coated surface to the image display member; irradiatingUV rays for photocuring; and thereafter heating the whole forheat-curing of the heat- and photocurable resin composition locatedbetween the light shielding layer and the image display member (PatentLiterature 2).

CITATION LIST Patent Literature

Patent Literature 1: WO2010/027041

Patent Literature 2: WO2008/126860

SUMMARY OF INVENTION Technical Problem

However, according to the technology of Patent Literature 2, althoughthe problems concerned in Patent Literature 1 can be expected to besolved, it is required to use a thermal polymerization initiator inaddition to a photopolymerization initiator at the same time, and toperform a thermal polymerization process as well as aphotopolymerization process. Therefore, there have been problems that aninitial investment for the thermal polymerization process becomeslarger, and that the storage stability of the heat- and photocurableresin composition is reduced. Furthermore, when the light-transmissivecover member including the heat- and photocurable resin compositioncoated thereon is laminated to the image display member, the resincomposition is not subjected to a curing process yet. As a result, theresin composition is eliminated from between the light shielding layerand the image display member. Accordingly, a step formed between thelight shielding layer and the surface of the light-transmissive covermember is not canceled. It is also concerned that air bubbles aregenerated, and an interlayer peeling between the light-transmissivecover member and the resin is caused.

An object of the present invention is to solve the above-describedproblems associated with conventional technologies, and to manufacturean image display apparatus by laminating an image display member and alight-transmissive cover member disposed on the surface side of theimage display member via a cured resin layer of a photocurable resincomposition wherein the photocurable resin composition between the lightshielding layer the image display member can be sufficiently photocuredand a step formed between the light shielding layer and thelight-transmissive cover member can be canceled without the use of athermal polymerization process and without being eliminated from betweenthe light shielding layer and the image display member, and tomanufacture the image display apparatus solely by a photopolymerizationprocess.

Solution to Problem

The inventors have found that the light-transmissive cured resin layerbetween the light shielding layer and the image display member can besufficiently photocured without being excessively eliminated frombetween the light shielding layer and the image display member, and thestep formed between the light shielding layer and the light shieldinglayer formation-side surface of the light-transmissive cover member canbe canceled, by coating the surface of the light-transmissive covermember including the light shielding layer or the surface of the imagedisplay member with a liquid photocurable resin composition that doesnot contain a thermal polymerization initiator in a thickness thickerthan that of the light shielding layer, and thereafter irradiating UVrays in that state for curing so that the image display member and thelight-transmissive cover member are laminated to each other via such alight-transmissive cured resin layer. Thus, the present invention hasbeen completed.

That is, the present invention is a method of manufacturing an imagedisplay apparatus wherein an image display member and alight-transmissive cover member having a light shielding layer formedaround an outer edge of the cover member are laminated to each other viaa light-transmissive cured resin layer formed from a liquid photocurableresin composition such that the light shielding layer-formed surface ofthe light-transmissive cover member is arranged on the image displaymember side. The manufacturing method includes the following steps (A)to (C):

<Step (A)>

coating the light shielding layer formation-side surface of thelight-transmissive cover member or the surface of the image displaymember with the liquid photocurable resin composition in a thicknessthicker than that of the light shielding layer so that a step formed bythe light shielding layer and the light shielding layer formation-sidesurface of the light-transmissive cover member is canceled;

<Step (B)>

irradiating UV rays to the coated photocurable resin composition forcuring to form the light-transmissive cured resin layer; and

<Step (C)>

bonding the light-transmissive cover member with the image displaymember such that the light shielding layer and the light-transmissivecured resin layer are located inside.

Advantageous Effects of Invention

In the method of manufacturing an image display apparatus according tothe present invention, the liquid photocurable resin composition thatdoes not contain a thermal polymerization initiator is coated on thesurface of the light-transmissive cover member including the lightshielding layer or on the surface of the image display member in athickness thicker than that of the light shielding layer, and thereafterUV rays are irradiated in that state for curing to form thelight-transmissive cured resin layer. Then, the image display member andthe light-transmissive cover member are laminated to each other via thelight-transmissive cured resin layer. Accordingly, thelight-transmissive cured resin layer between the light shielding layerand the image display member can be sufficiently photocured withoutbeing excessively eliminated from between the light shielding layer andthe image display member. Furthermore, the step formed between the lightshielding layer and the light shielding layer formation-side surface ofthe light-transmissive cover member can be canceled.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is an illustrative drawing of the step (A) of the method ofmanufacturing an image display apparatus according to the presentinvention.

FIG. 1B is an illustrative drawing of the step (A) of the method ofmanufacturing an image display apparatus according to the presentinvention.

FIG. 1C is an illustrative drawing of the step (B) of the method ofmanufacturing an image display apparatus according to the presentinvention.

FIG. 1D is an illustrative drawing of the step (B) of the method ofmanufacturing an image display apparatus according to the presentinvention.

FIG. 1E is an illustrative drawing of the step (C) of the method ofmanufacturing an image display apparatus according to the presentinvention.

FIG. 2A is an illustrative drawing of a step (AA) of the method ofmanufacturing an image display apparatus according to the presentinvention.

FIG. 2B is an illustrative drawing of a step (BB) of the method ofmanufacturing an image display apparatus according to the presentinvention.

FIG. 2C is an illustrative drawing of a step (BB) of the method ofmanufacturing an image display apparatus according to the presentinvention.

FIG. 2D is an illustrative drawing of a step (CC) of the method ofmanufacturing an image display apparatus according to the presentinvention.

FIG. 3 is an illustrative drawing of the evaluation test on the adhesionstate of the light-transmissive cured resin layer.

FIG. 4A is an illustrative drawing of an embodiment of coating of thelight-transmissive cover member with the photocurable resin composition.

FIG. 4B is an illustrative drawing of an embodiment of coating of thelight-transmissive cover member with the photocurable resin composition.

FIG. 5 is an illustrative drawing of an embodiment of coating of thelight-transmissive cover member with the photocurable resin composition.

FIG. 6 is an illustrative drawing of an embodiment of coating of thelight-transmissive cover member with the photocurable resin composition.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the method of manufacturing an image display apparatusaccording to the present invention, which includes the steps (A) to (C),will be described it detail for each step with reference to thedrawings.

<Step (A) (Coating Step)>

First, as shown in FIG. 1A, a light-transmissive cover member 2including a light shielding layer 1 formed around an outer edge of onesurface thereof is prepared. Next, as shown in FIG. 1B, a surface 2 a ofthe light-transmissive cover member 2 is coated with a liquidphotocurable resin composition 3 in a thickness thicker than that of thelight shielding layer 1 so that a step 4 formed by the light shieldinglayer 1 and the light shielding layer formation-side surface 2 a of thelight-transmissive cover member 2 is canceled. Specifically, the wholeof the light shielding layer formation-side surface 2 a of thelight-transmissive cover member 2, including the surface of the lightshielding layer 1, is coated flat with the photocurable resincomposition 3 so that a step does not occur. Therefore, the photocurableresin composition 3 is coated in a thickness of preferably 1.2 to 50times, and more preferably 2 to 30 times the thickness of the lightshielding layer 1.

The photocurable resin composition 3 may be coated a plurality of timesto obtain a required thickness.

The light-transmissive cover member 2 has a light transmittance whichallows an image formed on the image display member to be visuallyrecognized. Examples of the light-transmissive cover member 2 mayinclude a plate-like material and a sheet-like material of glass, anacrylic resin, polyethylene terephthalate, polyethylene naphthalate, andpolycarbonate. These materials may be subjected to a single or doublesided hard coating treatment, an antireflection treatment and the like.The physical properties such as a thickness and an elasticity of thelight-transmissive cover member 2 can be determined depending on theintended use.

The light shielding layer 1 is provided for, for example, enhancing thecontrast of an image, and is obtained by performing coating with a paintcolored in black or the like by a screen printing method or the like,and then drying and curing the coat. The thickness of the lightshielding layer 1 is usually 5 to 100 μm, which corresponds to thethickness of the step 4.

The property of the photocurable resin composition 3 used in this stepis liquid. By using a liquid, the step 4 formed by the light shieldinglayer 1 and the light shielding layer formation-side surface 2 a of thelight-transmissive cover member 2 can be canceled. Here, a liquidindicates a substance having a viscosity of 0.01 to 100 Pa·s (at 25° C.,cone-plate rheometer, cone and plate C35/2, rotational speed 10 rpm).

Examples of such a photocurable resin composition 3 may include asubstance which contains, for example, radical photopolymerizablepoly(meth)acrylate such as polyurethane-based (meth)acrylate andpolyisoprene-based (meth)acrylate, and a photopolymerization initiator,main ingredients. Here, the term “(meth)acrylate” means to includeacrylate and methacrylate.

Preferred examples of the radical photopolymerizable poly(meth)acrylatemay include a (meth)acrylate-based oligomer having polyisoprene,polybutadiene or polyurethane as a backbone.

Preferred examples of the (meth)acrylate-based oligomer having apolyisoprene backbone may include an esterified product of a maleicanhydride duct of a polyisoprene polymer and 2-hydroxyethyl methacrylate(UC102 (polystyrene-equivalent molecular weight: 17000), Kuraray Co.,Ltd.; UC203 (polystyrene-equivalent molecular weight: 35000), KurarayCo., Ltd.; UC-1 (molecular weight: approximately 25000), Kuraray Co.,Ltd.).

Preferred examples of the (meth)acrylate-based oligomer having apolyurethane backbone may include an aliphatic urethane acrylate(EBECRYL 230 (molecular weight: 5000), DAICEL-ALLNEX Ltd.; UA-1, LightChemical Industries Co., Ltd.).

As the photopolymerization initiator, publicly known radicalphotopolymerization initiators can be used. Examples thereof may include1-hydroxy-cyclohexyl phenyl ketone (Irgacure 184, BASF Japan Ltd.),2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)benzyl]phenyl}-2-methyl-1-propan-1-one(Irgacure 127, BASF Japan Ltd.), benzophenone and acetophenone.

When the amount of the photopolymerization initiator based on 100 partsby mass of radical photopolymerizable poly(meth)acrylate is too small,curing during UV irradiation becomes insufficient. When the amount istoo large, an increase of an outgas due to cleavage tends to cause afoaming failure. Therefore, the amount of the photopolymerizationinitiator is preferably 0.1 to 5 parts by mass, and more preferably 0.2to 3 parts by mass.

The liquid photocurable resin composition 3 may further contain publiclyknown plasticizers (flexibility-imparting agents) which are compatiblewith the radical photopolymerizable poly(meth)acrylate. Examples of suchplasticizers may include a terpene-based hydrogenated resin,polybutadiene and polyisoprene. These plasticizers may also be used as atackifies as described later.

The photocurable resin composition 3 may also contain a reactivediluent. Preferred examples of the reactive diluent may include2-hydroxypropyl methacrylate, benzyl acrylate anddicyclopentenyloxyethyl methacrylate.

The photocurable resin composition 3 may further contain, as necessary,general additives, for example, an adhesion-improving agent such as asilane coupling agent, and an antioxidant.

The photocurable resin composition 3 may also contain a chain transferagent for adjusting a molecular weight. Examples of the chain transferagent may include 2-mercapto ethanol, lauryl mercaptan, glycidylmercaptan, mercaptoacetic acid, 2-ethylhexyl thioglycolate,2,3-dimethylcapto-1-propanol and α-methylstyrene dimer.

It is noted that the UV irradiation in the step (B) described later canfunction, in some cases, such that the initial adhesive strength (aso-called tackiness) of the photocurable resin composition 3 isdecreased, and the final adhesive strength is reduced. Therefore, aso-called tackifier is desirably mixed in the photocurable resincomposition 3. Examples of the tackifier used may include terpene-basedresins such as a terpene resin, a terpene phenol resin and ahydrogenated terpene resin; rosin resins such as a natural rosin, apolymerized rosin, a rosin ester and a hydrogenated rosin; and petroleumresins such as polybutadiene and polyisoprene. The mixed amount of sucha tackifier in 100 parts by mass of the photocurable resin compositionis preferably 40 to 70 parts by mass.

Although the base material of the photocurable resin composition 3 isthe above-described radical photopolymerizable poly(meth)acrylate, theradical photopolymerizable poly(meth)acrylate which has been previouslypolymerized can be contained as the base material in order to developthe tackiness-imparting effect of the tackifier more strongly. Examplesof such a polymerized material may include a copolymer of butyl acrylateand 2-hexyl acrylate, and an acrylic acid; and a copolymer of cyclohexylacrylate and a methacrylic acid.

<Step (B) (Curing Step)>

Next, as shown in FIG. 1C, UV rays are irradiated to the coat of thephotocurable resin composition 3 formed in the step (A) for curing toform a light-transmissive cured resin layer 5 (FIG. 1D). By the curing,the light-transmissive cured resin layer 5 between the light shieldinglayer 1 and the image display member 6 can be sufficiently photocuredwithout being excessively eliminated from between the light shieldinglayer 1 and the image display member. The level of the curing is suchthat the curing rate (gel fraction) of the light-transmissive curedresin layer 5 is preferably 90% or more, and further preferably 95% ormore. Here, the curing rate (gel fraction) is a value defined as a ratio(consumption ratio) of the present amount of a (meth)acryloyl groupafter UV irradiation to the present amount of a (meth)acryloyl groupbefore UV irradiation in the photocurable resin composition 3. Thelarger this value is, the further the curing proceeds.

The curing rate (gel fraction) can be calculated by substituting in amathematical expression (1) below an absorption peak height (X) from thebaseline at 1640 to 1620 cm⁻¹ in the FT-IR measurement chart of theresin composition layer before UV irradiation, and an absorption peakheight (Y) from the baseline at 1640 to 1620 cm⁻¹ in the FT-IRmeasurement chart of the resin composition layer after UV irradiation.Curing rate (%)={(X−Y)/X}×100  (1)

Regarding UV irradiation, the type; output and accumulated light amountof a light source are not particularly limited as long as the curing canbe performed so as to have a curing rate (gel fraction) of preferably90% or more, and a publicly known process condition for radicallyphotopolymerizing (meth)acrylate with UV irradiation can be adopted.

<Step (C) (Bonding Step)>

Next, as shown in FIG. 1E, the light-transmissive cover member 2 isbonded to an image display member 6 on the side of thelight-transmissive cured resin layer 5. The bonding can be performedunder pressure at 10° C. to 80° C. using a publicly known pressurebonding apparatus. Accordingly, the image display member 6 and thelight-transmissive cover member 2 are laminated to each other via thelight-transmissive cured resin layer 5 to obtain an image displayapparatus 10.

Examples of the image display member 6 may include a liquid crystaldisplay panel, an organic EL display panel, a plasma display panel and atouch panel. Here, the touch panel means an image display and inputpanel in which a display element such as a liquid crystal display paneland a position input device such as a touch pad are combined.

The light transmittance level of the light-transmissive cured resinlayer 5 may be such that an image formed on the image display member 6can be visually recognized.

Although an example in which the photocurable resin composition iscoated on the light shielding layer-side surface of thelight-transmissive cover member has been described in FIG. 1A to FIG.1E, an example in which the photocurable resin composition is coated onthe surface of the image display member will be described in FIG. 2A toFIG. 2D below. The same reference numerals assigned in FIG. 1A to FIG.1E and in FIG. 2A to FIG. 2D represent the same components.

<Step (AA) (Coating Step)>

First, as shown in FIG. 2A, the photocurable resin composition 3 iscoated flat on the surface of the image display member 6. The coatedthickness in this case is preferably 1.2 to 50 times, and furtherpreferably 2 to 30 times the thickness of the light shielding layer sothat the step formed by the light shielding layer and the lightshielding layer formation-side surface of the light-transmissive covermember is canceled.

The coating of the photocurable resin composition 3 may be performed aplurality of times to obtain a necessary thickness.

<Step (BE) (Curing Step)>

Next, as shown in FIG. 2B, UV rays are irradiated to the photocurableresin composition 3 coated in the step (AA) for curing to form thelight-transmissive cured resin layer 5 (FIG. 2C). By curing thecomposition in this manner, the light-transmissive cured resin layer 5between the light shielding layer and the image display member can besufficiently photocured without being eliminated from between the lightshielding layer 1 and the image display member 6. The level of thecuring is such that the gel fraction of the light-transmissive curedresin layer 5 is preferably 90% or more, and more preferably 95% ormore.

<Step (CC) (Bonding Step)>

Next, as shown in FIG. 2D, the light-transmissive cover member 2 isbonded to the light-transmissive cured resin layer 5 of the imagedisplay member 6 on the side of the light shielding layer 1. The bondingcan be performed under pressure at 10 to 80° C. using a publicly knownpressure bonding apparatus. Accordingly, the image display member 6 andthe light-transmissive cover member 2 are laminated to each other viathe light-transmissive cured resin layer 5 to obtain the image displayapparatus 10.

Examples of the image display member 6 may include a liquid crystaldisplay panel, an organic EL display panel, a plasma display panel and atouch panel.

The light transmittance level of the light-transmissive cured resinlayer 5 may be such that an image formed on the image display member 6can be visually recognized.

EXAMPLES

The present invention will be specifically described by way of examplesbelow.

Example 1

(Step (A) (Coating Step))

First, a glass plate having a size of 45 (w)×80 (l)×0.4 (t) mm wasprepared. An entire region of the outer edge of the glass plate wascoated with a photocurable black ink (MRX Ink, Teikoku Printing InksMfg. Co., Ltd) by a screen printing method so as to form a lightshielding layer having a dry thickness of 40 μm and a width of 4 mm. Thecoated black ink was dried to prepare a glass plate with a lightshielding layer.

Also, 6 parts by weight of polyisoprene methacrylate (UC102, KurarayCo., Ltd.) as a radical photopolymerizable poly(meth)acrylate, 15 partsby weight of dicyclopentenyloxyethyl methacrylate and 5 parts by weightof lauryl methacrylate as a reactive diluent, 20 parts by weight ofpolybutadiene (Polyvest 110, Evonik Japan. Co., Ltd.) as a plasticizer,1 part by weight of a photopolymerization initiator (Irgacure 184, BASFJapan Ltd.) and 53 parts by weight of a hydrogenated terpene resin(Clearon M105, Yasuhara Chemical Co., Ltd.) as a tackifies wereuniformly mixed to prepare a photocurable resin composition. Theviscosity (cone-plate rheometer, 25° C., cone and plate C35/2,rotational speed 10 rpm) of this photocurable resin composition wasapproximately 6 Pa·s.

Next, the photocurable resin composition was discharged on the entirelight shielding layer-formed surface of the glass plate including thelight shielding layer with a resin dispenser to form a photocurableresin composition film having an average thickness of 200 μm. Thephotocurable resin composition film was formed so as to be substantiallyspread over the entire region of the light shielding layer as shown inFIG. 1B in a thickness thicker by 160 μm than the light shielding layerhaving a thickness of 40 μm.

(Step (B) (Curing Step))

Next, the photocurable resin composition film was irradiated with PITrays having an intensity of 50 mW/cm² for 60 seconds so that theaccumulated light amount becomes 3000 mJ/cm², using a UV irradiationdevice (LC-8, Hamamatsu Photonics K.K.), to cure the photocurable resincomposition film. In this manner, a light-transmissive cured resin layerwas formed.

The photocurable resin composition film after UV irradiation, that isthe light-transmissive cured resin layer, had a curing rate ofapproximately 92%. The curing rate was calculated by using as an indexan absorption peak height from the baseline at 1640 to 1620 cm⁻¹ in theFT-IR measurement chart.

Furthermore, the tackiness of the surface of the light-transmissivecured resin layer was 110 N/cm², based on a measurement by a probe tackmethod using a tacking tester (TAC-II, Rhesca Co., Ltd.).

(Step (C) (Bonding Step))

Next, the glass plate obtained in the step (B) was placed on the surfaceof a laminated polarizing plate of a liquid crystal display elementhaving a size of 40 (W)×70 (L) mm so that the light-transmissive curedresin layer side of the glass plate is on the polarizing plate side.Then, pressure was applied from the glass plate side with a rubberroller so that the glass plate was bonded to the liquid crystal displayelement. When the bonded liquid crystal display element was visuallyobserved from the glass plate side, air bubbles were not observed aroundthe light shielding layer.

<Evaluation>

The product obtained in each of the steps in Example 1 was visuallyobserved on whether or not air bubbles exist in the boundary between thelight shielding layer and the photocurable resin composition film layeror the light-transmissive cured resin layer, as will be described below.In addition, the adhesion state of the liquid crystal display apparatuswas evaluated as will be described below.

(Existence of Air Bubbles)

The product obtained in each of the steps in Example 1 was visuallyobserved on whether or not air bubbles exist in the boundary between thelight shielding layer and the photocurable resin composition film layeror the cured resin layer. As a result, air bubbles were not observed inthe product obtained in any of the steps and in the final liquid crystaldisplay apparatus.

(Evaluation of Adhesion State)

When preparing a liquid crystal display apparatus, a glass base 30having a size of 40 (W)×70 (L) mm was used instead of a liquid crystaldisplay element. A glass plate 31 including a light-transmissive curedresin layer formed thereon was bonded to the glass base 30 on thelight-transmissive cured resin layer side into a cross shape. Thus, aglass connection body was obtained. Then, whip the glass base 30positioned on the lower side of the connection body was fixed, the glassplate 31 positioned on the upper side was peeled off directly upward.Then, the peeling property was visually observed, and the adhesion statewas evaluated as “A” in accordance with the criteria below.

Rank: Criteria

A: When aggregation peeling occurred

B: When both aggregation peeling and interface peeling existed.

C: When interface peeling occurred

Example 2

A liquid crystal display apparatus and a glass connection body formeasuring an adhesion strength were prepared in the same manner as inExample 1, except that in the step (A) (Coating step) of Example 1, thephotocurable resin composition film was formed so as to be spread overapproximately 70% of the width of the light shielding layer. Then,observation was performed on whether or not air bubbles exist, and theadhesion state was evaluated. As a result, even when the photocurableresin composition film was formed to be spread over approximately 70% ofthe width of the light shielding layer, air bubbles did not exist in theproduct obtained in each step and in the final liquid crystal displayapparatus in Example 2, and the adhesion state was also evaluated as“A.”

Example 3

A liquid crystal display apparatus and a glass connection body formeasuring an adhesion strength were prepared in the same manner as inExample 1, except that in the step (A) (Coating step) of Example 1, thephotocurable resin composition film formed had a thickness ofapproximately 1.2 times the thickness of the light shielding layer.Then, observation was performed on whether or not air bubbles exist, andthe adhesion state was evaluated. As a result, when the photocurableresin composition film formed had a thickness of approximately 1.2 timesthe thickness of the light shielding layer, air bubbles did not exist inthe product obtained in each step and in the final liquid crystaldisplay apparatus in Example 3, and the adhesion state was alsoevaluated as “A.”

Example 4

A liquid crystal display apparatus and a glass connection body formeasuring an adhesion strength were prepared in the same manner as inExample 1, except that in the step (A) (Coating step) of Example 1, asshown in FIG. 4A, a photocurable resin composition 3 a was coated in thesame thickness as that of the light Shielding layer 1 without beingspread over the light shielding layer 1, and further, as shown in FIG.4B, a photocurable resin composition 3 b was coated so as to be spreadover the light shielding layer 1. Then, observation was performed onwhether or not air bubbles exist, and the adhesion state was evaluated.As a result, even when the photocurable resin composition wasmulti-layered, air bubbles did not exist in the product obtained in eachstep and in the final liquid crystal display apparatus in Example 4, andthe adhesion state was also evaluated as “A.”

Comparative Example 1

A liquid crystal display apparatus and a glass connection body formeasuring an adhesion strength were prepared in the same manner as inExample 1, except that in the step (A) (Coating step) of Example 1, thephotocurable resin composition 3 was spread over an entire region of thelight shielding layer 1, but had a thickness of 30 μm thinner than thatof the light shielding layer 1, as shown in FIG. 5. Then, observationwas performed on whether or not air bubbles exist, and the adhesionstate was evaluated. As a result, although air bubbles were not observedin the product obtained in the step (A), air bubbles were observed inthe product obtained in the step (C). The adhesion state was alsoevaluated as “A.”

Comparative Example 2

A liquid crystal display apparatus, and a glass connection body formeasuring an adhesion strength were prepared in the same manner as inExample 1, except that in the step (A) (Coating step) of Example 1, asshown in FIG. 6, the photocurable resin composition 3 was not formed soas to be spread over the light shielding layer 1, and was coated thinnerthan the light shielding layer 1. Then, observation was performed onwhether or not air bubbles exist, and the adhesion state was evaluatedresult, although air bubbles were not found in the product obtained inthe step (A), air bubbles were found in the product obtained in thebonding step of the step (C). The adhesion state was also evaluated as“A.”

Comparative Example 3

A liquid crystal display apparatus and a glass connection body formeasuring an adhesion strength were prepared in the same manner as inExample 1, except that in the step (A) of Example 1, the photocurableresin composition was not coated on the glass plate, but formed on arelease film; UV irradiation similar to the step (B) of Example 1 wasperformed to form a light-transmissive cured resin layer of thephotocurable resin composition on the release film; and thelight-transmissive cured resin layer was transferred on the glass plateincluding the light shielding layer formed thereon. Then, observationwas performed on whether or not air bubbles exist, and the adhesionstate was evaluated. As a result, air bubbles were found around the stepof the light shielding layer when the light-transmissive cured resinlayer was transferred. Air bubbles were also observed in the productobtained in the following step (C). The adhesion state was evaluated as“B.”

INDUSTRIAL APPLICABILITY

According to the method of manufacturing an image display apparatus ofthe present invention, the light-transmissive cured resin layer betweenthe light shielding layer and the image display member can besufficiently photocured without being excessively eliminated frombetween the light shielding layer and the image display member.Furthermore, the step formed between the light shielding layer and thelight shielding layer formation-side surface of the light-transmissivecover member can be canceled. Therefore, the manufacturing methodaccording to the present invention is useful in industrial manufacturingof information terminals such as a smartphone equipped with a touchpanel, and a touch pad.

REFERENCE SIGNS LIST

-   1 Light shielding layer-   2 Light-transmissive cover member-   2 a (Light shielding layer formation-side) surface of    light-transmissive cover member-   3, 3 a, 3 b Photocurable resin composition-   4 Step-   5 Light-transmissive cured resin layer-   6 Image display member-   10 Image display apparatus-   30 Glass base-   31 Glass plate

The invention claimed is:
 1. A method of manufacturing an image displayapparatus wherein an image display member and a light-transmissive covermember having a light shielding layer formed around an outer edge of thecover member are laminated to each other via a light-transmissive curedresin layer formed from a liquid photocurable resin composition suchthat a surface of the light-transmissive cover member on which the lightshielding layer is formed is arranged on a side of the image displaymember, the manufacturing method comprising the following steps (A) to(C): <Step (A)> coating the surface of the light-transmissive covermember on which the light shielding layer is formed with the liquidphotocurable resin composition in a thickness thicker than that of thelight shielding layer so that a step formed by the light shielding layerand the surface of the light-transmissive cover member on which thelight shielding layer is formed is canceled; <Step (B)> irradiating UVrays to the coated photocurable resin composition for curing to form alight-transmissive cured resin layer having a cure rate of 90% or moreand less than 100%; and <Step (C)> bonding the light-transmissive covermember with the image display member such that the light shielding layerand the light-transmissive cured resin layer are between thelight-transmissive cover member and the image display member; wherein inthe step (A), a mixed amount of a tackifier in 100 parts by mass of theliquid photocurable resin composition is 40 to 70 parts by mass, in thestep (B), an initial adhesive strength of the coated photocurable resincomposition, which is cured to form the light-transmissive cured resinlayer having a cure rate of 90% or more and less than 100%, is increasedby the tackifier, and in the step (C), the bonding is performed underpressure at 10 to 80° C. using a pressure bonding apparatus.
 2. Themanufacturing method according to claim 1, wherein the image displaymember is a liquid crystal display panel, an organic EL display panel ora touch panel.
 3. The manufacturing method according to claim 1, whereinin the step (A), the photocurable resin composition is coated in athickness 1.2 to 50 times a thickness of the light shielding layer. 4.The manufacturing method according to claim 1, wherein in the step (B),the curing rate of the light-transmissive cured resin layer is 95% ormore and less than 100%.
 5. The manufacturing method according to claim1, wherein the liquid photocurable resin composition containspolyurethane-based (meth)acrylate or polyisoprene-based (meth)acrylate,and a photopolymerization initiator.
 6. The manufacturing methodaccording to claim 1, wherein the tackifier is selected from the groupconsisting of petroleum resins, polybutadiene, and polyisoprene.
 7. Themanufacturing method according to claim 1, wherein the tackifier isselected from the group consisting of polybutadiene and polyisoprene. 8.The manufacturing method according to claim 1, wherein the mixed amountof the tackifier in 100 parts by mass of the liquid photocurable resincomposition is 50 to 70 parts by mass.
 9. A method of manufacturing animage display apparatus wherein an image display member and alight-transmissive cover member having a light shielding layer formedaround an outer edge of the cover member are laminated to each other viaa light-transmissive cured resin layer formed from a liquid photocurableresin composition such that a surface of the light-transmissive covermember on which the light shielding layer is formed is arranged on aside of the image display member, the manufacturing method comprisingthe following steps (A) to (C): <Step (A)> coating the surface of thelight-transmissive cover member on which the light shielding layer isformed with the liquid photocurable resin composition over the lightshielding layer in a thickness thicker than that of the light shieldinglayer so that a step formed by the light shielding layer and the surfaceof the light-transmissive cover member on which the light shieldinglayer is formed is canceled; <Step (B)> irradiating UV rays to thecoated photocurable resin composition for curing to form alight-transmissive cured resin layer having a cure rate of 90% or moreand less than 100%; and <Step (C)> bonding the light-transmissive covermember with the image display member such that the light shielding layerand the light-transmissive cured resin layer are between thelight-transmissive cover member and the image display member; wherein inthe step (A), a mixed amount of a tackifier in 100 parts by mass of theliquid photocurable resin composition is 40 to 70 parts by mass, in thestep (B), an initial adhesive strength of the coated photocurable resincomposition, which is cured to form the light-transmissive cured resinlayer having a cure rate of 90% or more and less than 100%, is increasedby the tackifier, and in the step (C), the bonding is performed underpressure at 10 to 80° C. using a pressure bonding apparatus.
 10. Amethod of manufacturing an image display apparatus wherein an imagedisplay member and a light-transmissive cover member having a lightshielding layer formed around an outer edge of the cover member arelaminated to each other via a light-transmissive cured resin layerformed from a liquid photocurable resin composition such that a surfaceof the light-transmissive cover member on which the light shieldinglayer is formed is arranged on a side of the image display member, themanufacturing method comprising the following steps (A) to (C): <Step(A)> coating the surface of the light-transmissive cover member on whichthe light shielding layer is formed with the liquid photocurable resincomposition in a thickness thicker than that of the light shieldinglayer so that a step formed by the light shielding layer and the surfaceof the light-transmissive cover member on which the light shieldinglayer is formed is canceled; <Step (B)> irradiating UV rays to thecoated photocurable resin composition for curing to form alight-transmissive cured resin layer having a cure rate of 90% or moreand less than 100%; and <Step (C)> bonding the light-transmissive covermember with the image display member such that the light shielding layerand the light-transmissive cured resin layer are between thelight-transmissive cover member and the image display member; wherein inthe step (A), a mixed amount of a tackifier in 100 parts by mass of theliquid photocurable resin composition is 40 to 70 parts by mass, in thestep (B), an initial adhesive strength of the coated photocurable resincomposition, which is cured to form the light-transmissive cured resinlayer having a cure rate of 90% or more and less than 100%, havingtemporarily cured is increased by the tackifier, in the step (C), thebonding is performed under pressure at 10 to 80° C. using a pressurebonding apparatus, and the tackifier is selected from the groupconsisting of terpene-based resins, a terpene resin, a terpene phenolresin, a hydrogenated terpene resin, rosin resins, a natural rosin, apolymerized rosin, a rosin ester, a hydrogenated rosin, petroleumresins, polybutadiene, and polyisoprene.